Victorian Railways Dd Class
The Dd Class is a 4-6-0 "Ten Wheeler" type of steam locomotive which ran on the Victorian Railways of Australia from 1902 History At the turn of the century, the VR's fleet consisted mostly of aging 4-4-0 and 0-6-0 designs, the former were the VR's express passenger locomotives (namely the Old A, New A and Aa Class locomotives). The Dd Class entered service in 1902 as a new express passenger locomotive class 261 Dd Class locomotives were built across the world from various manufacturers in Australia, the United Kingdom and the United States The Dd Class was built with a saturated steam boiler and a Belpaire firebox. When they were first introdiced, they has a very British like appearance (then again, so did most locomotives on the VR before then) with a low running plates with splashers above the wheels and a narrow cab. Later on they were rebuilt with higher running plates above the driving wheels and a wider cab of Canadian design, which would become standard features on future VR designs They continued their lives on top link passenger duties across Victoria until the the late 00 years where Victoria (like the rest of the world) saw a massive boom in traffic, thus massively increasing workloads, where the Dd found itself incapable of keeping up, thus in 1907 they were replaced by the larger and more powerful A2 Class 4-6-0's. Despite this, their axle loads allowed them to be relegated branchline duties, where they served well as branch line passenger locomotives for the next 50 years In 1914, to increase performance on their duties, the Dd's were refitted with superheated boilers as opposed to saturated boilers, which increased their tractive effort (along with all of the A2 Class locomotives, superheated boilers were to become standard on all future VR designs) In 1922 a renumbering and reclassing of VR locos saw the class being divided into variants, the D1's being the original locos with saturated steam boilers, the D2's being the locomotives being the newer superheated steam boilers Withdrawals and scrappings of Dd's commenced as early as 1929 being rendered obsolote by larger and more powerful K Class and N Class 2-8-2 locomotives, with the saturated D1 Class being the first to go with 120 being scrapped by 1951. The remaining D1's being shunters, the D2's being suburban goods and branchline mixed traffic engines and the D3's being on branchline and mainline services. Until 1954 came the time for the Dd variants to be superseded by the J Class 2-8-0 and T Class Bo-Bo diesel locomotives on even brancline duties D3 Class In 1922, the K Class 2-8-0's were intoduced to handle branch line goods duties and had superior performance to any Dd variant, which led to several Dd's being refitted with new boilers based on that of the K Class engines in 1929, which was so successful that 94 Dd's were converted to D3's between 1929 and 1947 Said upgrades increasing speed and power considerably, allowing for faster timetables as well as being more efficient than their original selves Dde tank engine The Dd design was so successul than the design was adapted into a tank engine design known as the Dde Class 4-6-2T in 1908. This variant of the Dd was built due to increased traffic on Melbourne's suburban network and delays on electrification with the need for more powerful locomotives to replace the 19th century sururban passenger tank engines After electrification in 1919, the Dde's became redundant and two were converted to Dd tender engines In the 1920's, many Dde's were scrapped or relegated to shunters at suburban stations In 1929 the Dde's were reclassed into the D4 Class after the reclassing of the Dd variants and were refitted with superheated boilers Preservation D1 Class None of the original D1 Class locomotives survive D2 Class D2 604 is the sole survivor of the D2 Class, preserved at the ARHS Museum at North Williamstown D3 Class OPERATIONAL *D3 639 was restored by Steamrail Ballarat and has worked on the Victorian Goldfields Railway in 2013 D3 635 is on display at the ARHS museum at North Williamstown. 13 other D3's are also preserved, some as future resotrarion projects, static displays or as spare parts D4 Class D4 268 is the sole survivor of the D4 Class, preserved at the ARHS Museum at North Williamstown Specifications D1/D2 Weigh 96.3 tonnes with an axle load of 13.2 tonnes. The engine having two cylinders with an 18 inch bore by a 26 inch stroke (457 x 660 mm). The locomotive has a boiler pressure of 175 psi and has a tractive effort of 20,530 lbf. The firebox possesses a grate area of 21.2 square feet (1.97 m^2) Their driving wheels are 61 inches (1.55 meters) in diameter Their tenders are capable of holding 5.1 tonnes and 4220 gallons (19,200 litres) of water D3 Weigh 101.2 tonnes with an axle load of 13.9 tonnes. The bore of the engine's cylinders being increased by an inch compared to the original D1/D2 classes (19 inches or 483 mm) and the boiler pressure decreased by 5 psi (170 psi) with tractive effort increased to 22,600 lbf. The firebox possesses a grate area of 25 square feet (2.3 m^2) D4 An axle load of 14.7 tonnes Their bunkers are capable of holding 2.8 tonnes of coal and their tanks capable of holding 1700 gallons (7700 litres) of water Trivia *The Dd were the predecessor for all modern VR designs *The Dd Class is notable for being the last class of locomotives built by Phoenix Foundry in Ballarat 5900180613_31fb9a7d82_o.jpg|D2 604 7513462710_42fd14e280_z.jpg|D4 268 Category:Steam Locomotives Category:Tender Engines Category:Victorian Railways Category:Six Coupled Locomotives Category:4-6-0 Steam Locomotives Category:Australian Locomotives Category:4-6-0 Locomotives Category:Built in 1902 Category:Built in 1908 Category:Built in 1929